TOXICITY ASSESSMENT OF ENGINEERED NANOPARTICLES USING ALGAE CHLORELLA VULGARIS

The use of nanoparticles covers new spheres of production every year. Their release into the environment is possible at any stage of their lifespan: from the manufacturing process to the utilization in the final product; therefore potential risks they pose for various environmental objects should be evaluated. The purpose of this work was to assess the effect of technogenic nanoparticles on Chlorella vulgaris growth and photosynthetic activity. Toxic properties of three types of nanoparticles TiO2 with a size of 100 to 190 nm, SiO2 with dimensions of 10-15 nm and 100-120 nm have been studied. Chlorella vulgaris Beijer alga was used as test organism. The evaluation of nanoparticles toxicity was based on changes in the relative delayed fluorescence index (RDFI), which characterizes the photosynthetic activity of microalgae. The effect on the growth of the test culture was determined from the optical density (OD) of the algal suspension. It was found that the TiO2 nanoparticles slightly reduced the growth and activity of the cell photosynthetic apparatus. Large particles of SiO2 proved to be more toxic than smaller ones. For nanoparticles of 100-120 nm size , the EC50 value according to the OD index was 8 mg/dm3, while the particles measuring 10-15 nm did not show a significant effect on the growth of the culture. Large SiO2 particles also appeared more toxic than small particles, judging by RDFI parameter.

nanoparticles, nanotoxicity, Chlorella vulgaris, biotesting, delayed fluorescence of chlorophyll, optical density